Mitsubishi MUZ-A18YV Service Manual page 33

Indication
Abnormal point
LED 1 LED 2
(Red) (Yellow)
Once Lighting Current protection
Twice Lighting High-pressure protection When the indoor gas pipe temperature exceeds 55˚C during heating.
Twice Lighting Defrosting in cooling
Discharge temperature
3 times Lighting
protection
Lighting Low discharge
4 times
temperature protection
5 times Lighting High-pressure protection
Indication
Abnormal point
LED 1 LED 2
(Red) (Yellow)
Lighting 5 times
Defrost thermistor
Initial-setting
11 times Lighting
9 times Lighting
Service mode
Symptom: Outdoor unit operates (The compressor operates at reduced frequency)
Detecting method
When the outdoor unit input current exceeds 14.5A.
When the indoor gas pipe temperature falls to 6˚C or below during cooling.
When the discharge temperature exceeds 104˚C.
When the state with low discharge temperature of which 37˚C or below
in COOL and 35˚C or below in HEAT lasts for 20 minutes.
When outdoor heat exchanger temperature thermistor detects 58: or
more.
Symptom: Outdoor unit operates.
Detecting method
When a short or open circuit occurs in the defrost thermistor during
heating.
When the initial-setting information from an indoor unit is now being read.
When the unit operates EMERGENCY OPERATION.
33
Check points
These symptoms do not mean any
abnormality of the product, but check
the following points.
• Air filter clogging
• Amount of gas
• Short cycle of indoor/outdoor air flow
Check points
• Check the characteristic of the defrost
temperature thermistor.
• Check the connector. (CN661)